Process for effecting bactericidal action by the aid of chlorine



Patented Jan. 25, 1 938 PROCESS FOR EFFECTING BACTERICIDAL ACTION BY THE AID OF CHLORINE -William M. Allison, New York, N. Y. No Drawing. Original application May 10, 1934,

Serial No. 724,914.

Divided and this application February 14, 1935, Serial No. 6,517

12 Claims.

This invention relates to process and compounds for effecting bactericidal action by the aid of chlorine and is herein illustrated as embodying bactericidal compounds having highly selective 5 action.

It is not essential to the present invention that a compound be prepared in a dry form or even approximately pure, in fact I have found that chlorine compounds of urea are very unstable when not in relatively dilute solution. It has been found that water carrying a little urea in solution maintains some content of active chlorine longer than does water lacking the urea. More chlorine without urea or one of its derivatives.

It has long been felt that a sterilizing medium was needed which, when applied to the sterilization of waters, would afl'ord the maintenance of its sterilizing action over relatively long periods of time. When chlorine alone in small amounts is applied to water supplies of cities or towns, the activechlorine is dissipated in a very short time by the presence of both inorganic and organic mat- .ter and its sterilizing effect is lost in a very short time. This is primarily due to the fact that chlorine applied alone to waters has no selective action and will combine very quickly with any organic or oxidizable inorganic matter which may be .present. Hence its sterilizing action. is lost very quickly.

I have found that even in the presence of large quantities of organic or inorganic materials, in solutions which quickly dissipate the chlorine when the chlorine is present as simple chlorine in solution or as any of the hypochlorites that the presence of small quantities of urea or one of its compounds will prevent the said dissipation of the available chlorine for a relatively long period of available chlorine, adding enough so that the water contained less than one part per million of available chlorine.

It is found that the dry urea may be added directly to the water containing available chlorine or water containing a relatively large amount 01' urea and available chlorine may be used as a minor solution for treating the water or solution to besterilized. Good results have been obtained when some alkaline buffer salt such as alkaline phosphates or carbonates were present. In the presence of the small amounts of available chlorine mentioned above, the urea is very stable and nitrites or nitrates do not accumulate in the urea.

solutions.

Chlorine, when added to water in excess of the amount required to sterilize over an extended period of time, produces characteristic objectionable taste and odor with resulting production of irritation to the human mucous menibranes when such solutions are applied thereto. Imaddition to this primarychlorinous taste and odor being produced in waters, secondary tastes and odors 'are produced by the interaction of the chlorine with phenols and other organic compound which may be present in the water supplies in very minute quantities and are not noticeable until such reaction with chlorine. Urea or one of its compounds added to such waters, prevents the production of objectionable chlorinous tastes '80 and odors even when in. relatively concentrated solution, and also prevents the formation of objectionable chlorophenols and other chemical combinations which are objectionable tothe taste and smelL. r T

It has also been found that guanidine or any of its compoundsor derivatives will produce the same .results, as did the urea when in solution. Apparently it is only necessary that at least one of the groups represented byrine in solution insofar as stabilizing such availw able chlorine to prolong its action in preventing s ime in paper mills and such surfaces in contact 5 with water, preventing and cleaning slime formations from the water surfaces of tube and other metal condensers used in power production and in the treatment of sewage eflluents and waste products to prevent pollution of streams and bodies of water.

I have found that the combination of urea or one of its compounds, guanidine or one of its compoundsor any of-its derivatives with chlorine in solution acts as well or better in the stabilization of the available chlorine and in eflecting' bettersterilization to accomplish the results desired.

In other words water carrying both available chlorine and-urea or guanidine, or their derivatives or compounds, is highly effective for treating waters used in factories, such as condenser waters, in which this combination of substances is highly effective in killing bacteria on tube surfaces and in removing accumulations of them on the tubes, -it isalso highlyeifective in keeping free from bacteriaother surfaces .in contact with water such as spray ponds, condenser surfaces, and paper mill equipment. It is also useful for treating water in various manufacturing processes to reduce the growth .of bacteria and other microorganisms. .Such organisms have been found toattack stock in paper mills and in other ways are deleterious.

Suitablecompounds of urea for such purposes are urea hydrochloridc, phenyl urea, and ure-- :thane. Suitable compounds of guanidine are guanadine hydrochloride, diphenyl guanidine, andguanoguanldine.

If it is desired to add chlorine in another form,

the urea or guanidine compounds carrying chlo- .sists in dissolving 'in it urea with chlorine, the

urea being present in less than one part per mil lion, and the chlorine being present in an amount. equal to several times the amount of urea.

4. The process of purifying water which consists in dissolving in it an amount of a substance containing the group represented by the amount not exceeding one part per million of the water, and with an amount of chlorine more than twice as great.

.5. The process of purifying waterwhich consists-in dissolving in it a guanidine compound and chlorine.

6. The process of purifying water which consists in dissolving in it a guanidine and a compound carrying available chlorine.

7. The process of purifying water which consists in dissolving in it a'guanidine compound carrying chlorine.

8. The process of purifying water which consists in dissolving in it an amount of a substance carrying the group represented by HzN-("l-NH: and also carrying chlorine; so' that the-water carries approximately 'one part per million of available chlorine. 9. The process of removing deposits on inor- 'gani'c surfaces which"'consists in exposing them to water carrying a urea compound and available chlorine.

10. 'I'heprocess of removing deposits on iriorganlc surfaces which consists in exposing them 'to water carrying ajguanidine compound and available chlorine.

' 11. In apr'ocess of water purificationthe step which comprises adding to water small quantities of carbamide and chlorine.

' .1 2. In .a process of water purification the step which comprises adding .carbamide and chlorine towater .m' 'the proportions of about 1 to '1 poundsof carbamideand about 4 to 16 pounds of chlorine respectively per million gallons of .water. W

WILLIAM M. ALLISON. 

